'General Hospital' casts 'Knot's Landing' star -- EXCLUSIVE

Donna Mills — best known for playing villainess Abby Ewing on Knot’s Landing — is joining the cast of General Hospital. EW has learned that Mills was the only choice to play a new (see: big) character — particularly because the writers are major fans of her old primetime soap.

Sadly, insiders won’t spill details about her character. She is expected to start appearing on the sudser in late February.

The addition of Mills caps off a big year for casting on GH, which celebrated its 50th anniversary last April. Executive Producer Frank Valentini lured back former stars like Genie Francis, Rick Springfield and even Richard Simmons to help celebrate the milestone.